


Demon

by MusicalFangirl00193



Category: The Mortal Instruments Series - Cassandra Clare
Genre: Demonic Possession, M/M, Mpreg, mentioned temporary character death
Language: English
Status: Completed
Published: 2017-10-04
Updated: 2017-10-06
Packaged: 2019-01-08 20:40:25
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 3,344
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12261678
Author URL: https://archiveofourown.org/users/MusicalFangirl00193/pseuds/MusicalFangirl00193
Summary: After being attacked and possessed by a demon, Alec discovers that he's pregnant, and the demon has moved from him to his unborn child.





	1. Chapter 1

“Alec!” Magnus yelled across the alleyway battlefield, causing me to turn just as I was hit by the projection of pure white light that the demon we were fighting was using as a weapon.

The light paralyzed me. I could still see and hear what was going on, but I couldn’t react to any of it. Which meant I could hear the demon run off, and I saw Magnus and Jace lean over me before I felt a sharp pain around my neck and down my spine, where the light had hit me, and passed out.

* * *

Someone was calling my name. I tried to open my eyes, but whatever the demon had done to me to keep me from moving was still working.

_“Oh, you’re awake,”_ an unfamiliar voice said from inside my own head.

I tried to speak, to demand to know who was in my head, to know where Magnus was, where Jace was, where I was.

_“Ah, ah, ah,”_ the voice said chidingly, _“I have complete control over your body Alec, there’s nothing you can do unless I allow it, so be a good little boy. The less you fight, the easier it will be for the both of us.”_

_“What do you want with me?”_ I demanded, trying to mask my fear from the thing in my head.

_“A life,”_ the demon said. _“I want to live a human life. And you’ve got the perfect one.”_

My eyes opened against my will and I saw Isabelle sitting next to the bed, running her whip through her hands.

“Izzy?” the demon asked with my mouth, with my memories.

“Alec!” Isabelle set her whip aside. “Are you okay?”

I wanted to say no, I wanted to tell her what was going on. What actually came out of my mouth was the opposite, “I’m fine, where are Magnus and Jace?”

“Jace is training with Clary,” Isabelle said, expression turning to a frown as she looked around. “I have no idea where Magnus is.”

I frowned as the demon sat me up. “How long was I unconscious?”

“Three days,” Isabelle said, picking up her whip again. “That demon really did a number on you.”

Isabelle’s phone rang while I argued with the demon in my head. “It’s Magnus,” she said, breaking me out of my internal argument as she answered the call.

“Hey Magnus,” she answered. “Yeah, he just woke up…I don’t care, bring Chairman Meow…Church needs the company…he won’t make Chairman hate you…I’ll see you when you get here,” she ended the call. “Magnus in on his way.”

I smiled a bit, even after all of this, all I wanted was to see my boyfriend. He might have a spell to exorcise the demon that was controlling my body.

_“It’s not that easy Alec. The only way I’m leaving your life is if I want to. And I don’t think that will happen for a long time,”_ the demon practically purred. _“Oh look, here comes Magnus. Behave yourself, or I’ll be forced to put you back to sleep.”_

I decided it would serve me better to do as the demon said, so I settled in to watch Magnus cross the room to the bed I was sitting in.

“Alexander, are you alright?” Magnus said, sitting on the edge of my bed.

“I’m fine Magnus,” the demon said, voice fond.

“Are you sure?” Magnus asked, fingers running everywhere he could, fingers glowing with magic. “You were unconscious for three days Alexander!” I could hear the panic rising in his voice.

“I’m fine Magnus,” the demon said again, taking Magnus’ hand and leading it down to cover my abdomen. “We both are.”

“Both?” Magnus asked, Izzy echoing in the background.

_“Asshole,”_ I hissed at the demon, _“Jace is the only one who knew.”_

_“Then it’s well past time for them to know,”_ the demon said with a chuckle before ignoring me in favor of Magnus.

“I’m pregnant, Magnus,” the demon said, putting my hands over Magnus’ on my stomach. “We’re going to be parents.”

“How is…how is that possible? Warlocks are sterile,” Magnus asked, “And we’re both men.”

“Are you trying to tell me that your magic has never done something unexpected?” the demon said gently. All of my reasons for not telling Magnus where flooding my mind. What if he left me? What if he tried to make me get rid of the baby? What if—Magnus did the one thing I had hoped he would do but had feared he wouldn’t.

Magnus threw his arms around me in a tight hug, laughing sobs shaking his body and mine, tears soaking the back of my shirt. “This is amazing, Alexander,” Magnus said, pulling back a bit and wiping at his eyes. “When did you find out, how far along are you?”

“About a week ago,” the demon said as I still reeled. “I think I’m about three months, but it’s not like I can go to a doctor on this.”

“I love you,” Magnus murmured, giving me a gentle kiss.

“I love you too,” I responded before realizing I had said that on my own. Where had the demon gone?

I poked around in my head for a moment before getting what was the equivalent of a _‘Gone fishin’'_ sign.

“Are you okay?” Magnus asked, fingers glowing with magic again. “Alexander?”

“I’m fine,” I said with a smile. “Just got a bit dizzy. I’m good.”


	2. Chapter 2

/|Dream|\

The nursery I found myself in was brightly decorated. The walls were pastel blue, and the crib, changing table, dresser, and rocking chair were a mixture of red and blue splatters that seemed like something Clary would do.

I looked into the crib and smiled softly at the small boy with black hair. I ran a gentle hand through his hair and he made a happy noise, opening his eyes. They were Magnus’ cat eyes, but with my blue coloring.

I leaned over to pick him up, but as I lifted him over the top of the crib, his eyes started changing color. By the time I had him settled against my chest, his eyes were completely black, not even any white showing.

“Hello Alec,” a familiar voice said, “Or should I say, _Mother_.”

“What are you doing to my son?” I hissed.

“Nothing at all Alec,” the demon said from my son. “You remember, I did the exact same thing to you.”

“Leave my son alone!”

/|End Dream|\

I shot up in bed with a gasp, covered in a cold sweat.

“Alexander?” Magnus sat up next to me, putting an arm around my shoulders. “Are you okay?”

I didn’t respond for a moment, trying to calm my racing heart.

“Alexander?” Magnus asked again, pulling me closer.

“I have to tell you something,” I murmured, turning and burying myself in Magnus’ arms.

“What is it?” Magnus asked, pressing a kiss to the top of my head.

“I didn’t tell you I was pregnant,” I murmured before pulling away to look at Magnus. “I was possessed by the demon that we had been fighting. It left, so I didn’t think it was important anymore. But, I just had a dream that…it was in the baby. His eyes turned black, and he spoke to me like an adult. I don’t want him to be like that.”

“Why didn’t you tell me this before?” Magnus asked, pulling me back in.

“He was gone. I didn’t want to worry you for no reason.”

“Demonic possession isn’t no reason Alexander,” Magnus told me.

“I’m sorry.”

“You don’t need to be sorry. Just…don’t keep secrets, we both know how that goes for us.”

“Okay,” I murmured, falling asleep against Magnus’ chest, knowing he would do everything in his power as High Warlock of Brooklyn to keep us all safe.

* * *

“You what?” Isabelle asked incredulously. Jace, for probably the first time in his life, was absolutely speechless.

“I told you,” I said with a sigh. “Three times.”

“So you’re saying,” Jace said slowly, mulling it over as he spoke. “You think that your unborn son is possessed by the demon that possessed you two months ago?”

“Yes,” Magnus answered. “I think I can exorcise the demon, but it has to be before he’s born. I need to look at a book in your library to be able to do the ritual.”

“Alright,” Jace said, leading the way to the library. “No way any nephew of mine is going to be demon possessed.”

Magnus stood in the middle of the room, spinning slowly, eyes scanning the shelves. “This one,” he said suddenly, walking to a shelf, pulling a book from about waist height.

“A bestiary?” Isabelle questioned. “You don’t have one?”

“Yours is more complete than anything I could find outside of an Institute,” Magnus said, laying the book down on Hodge’s old desk, flipping through it. “I think this is the kind of demon we’re up against,” he said, pointing to a page I couldn’t see.

Jace looked over Magnus’ shoulder and paled. “I’ve heard about these. Valentine told me they were the worst kind. Controlling a person’s body while their mind is trapped inside, unable to do anything. If you’re right, this has to be done before he’s born or else it’ll be too late.”

“I know,” Magnus said, closing the book. “Now that we know what we’re dealing with, I can use my spell books to do the exorcism.”

“How long?” I asked.

“Two months, if I hurry. This kind of demon requires a complex potion. It normally takes four months, but we don’t have that kind of time. Two months will be a rush, but it should be doable.”

“It will have to be. We can hold on that long, just do your best,” I said, kissing Magnus on the cheek.

“I’m going home to start the potion, I need you to stay here,” Magnus said, mind already racing through the potion. “I’ll come get you when it’s safe.” He paused on his way out the door, “You’ll be okay here, right?”

“I’ll be fine, Magnus,” I said fondly. “I did live here for almost eighteen years.”

“You know I still worry about you,” Magnus said, coming back from the door.

“I’ll be fine. I have Izzy and Jace if I need anything. You know they’re just as overprotective as you are. Now go, be careful.”

“I will,” Magnus promised with one more kiss. “I love you.”

“I love you too.”


	3. Chapter 3

/|Dream|\

“Magnus?” I called, walking down the hallway at our apartment. “Where are you?”

The door next to our bedroom was cracked, soft light spilling out into the hallway. I pushed the door open the rest of the way and saw Magnus standing next to the crib I’d seen in my previous dream.

“What are you doing?” I asked leaning against the door frame.

“Just watching him,” Magnus said, half turning to face me. “I can’t believe we made him. He’s perfect, how did we do that?”

“I don’t know,” I said with a laugh, stepping into the room. “We should get some sleep though, he’ll be up in two hours to eat.” I wrapped my arms around Magnus’ waist, burying my face between his shoulders. “Or maybe we could not get some sleep.”

Magnus smiled, turning around. “Do you have something planned Alexander?”

“I do,” I said with a smirk. “I think you’ll enjoy it too.”

“Lead the way,” Magnus said, releasing his hold on me and letting me pull him out of the room.

/|End Dream|\

“What do you think of Max?” I asked, fingers wrapped around a warm mug of tea.

Magnus paused for a moment in his ingredient preparation before continuing. “Would you be okay with that?” he asked, “He was your brother.”

“I think he’d be excited,” I said, playing with a small chip on the rim of the mug. “He always wanted to not be the youngest.”

“Then I think Max is a good name,” Magnus said.

I nodded, “Are you heading back to your workshop?”

“Yeah,” Magnus said, gathering his supplies. “Is Jace coming over?”

“Around noon,” I answered. “He’ll bring you lunch.”

“I’ll see you this evening,” Magnus said, rounding the table and pressing a kiss to the top of my head. “I love you.”

“Love you too,” I said, tilting my head back enough to get a proper kiss. “Good luck.”

“Oh baby,” Magnus said with a smirk and a spark of magic. “This is all skill.”

 

“It’s done.” Magnus collapsed on the bed next to me, exhausted. “It has to set for three days to reach full potency.”

“Is everything else ready?” I asked, moving closer to Magnus, allowing him to octopus as much as he liked.

“Yes,” Magnus yawned. “Everything ready for Friday. Tell blond one tomorrow, sleep now.”

“That sounds good,” I agreed, settling in for sleep as Magnus immediately passed out.

* * *

“Are you ready for this?” Isabelle asked, standing next to me as we watched Magnus prepare the ritual.

“I’m a bit nervous,” I admitted, “But this is necessary, for Max.”

Isabelle smiled, bittersweet at the reminder of both our younger brother and her nephew. “For Max,” she agreed, squeezing my hand as Magnus came over, wiping chalk dust from his hands.

“Ready?” I asked, taking his hand with my free hand.

“As I’ll ever be,” he answered, leading me into the center of the figure he had drawn. He handed me a vial of purple liquid. “You know when to take this?”

I nodded, holding the vial in both of my hands.

Magnus kissed my forehead before stepping back and picking up a large tome and reading from it in a language I couldn’t understand.

I listened carefully until I heard the phrase Magnus had drilled into me. I opened the vial and downed the potion. It tasted like every horrible thing in the world, but I kept it down as Magnus continued changing. As Magnus finished, I felt something shift in my stomach.

_“You think you’re so clever Alexander Lightwood,”_ the demon’s voice hissed in my mind, bright light filling my vision. _“Let’s see how well you think of yourself when you have nothing left.”_


	4. Chapter 4

Consciousness came back slowly, unfamiliar voices filling my ears. I waited until I was conscious enough to be able to move before opening my eyes.

“Hello,” a kind looking man greeted when I opened my eyes. “How do you feel?”

“Where am I?” I asked in lieu of answering.

“I’m not surprised you don’t recognize it,” the man said. “Magnus has redecorated several times since you’ve been unconscious. I think it’s his form of pacing.”

I considered his words for a moment, looking around the room again, noticing the signs of Magnus’ occupation of the room. “Where is he?” I asked, attempting to sit up but stopping with a hiss of pain.

The man helped me lay back, passing me a glass of water and several pills. “He’s in the next room with Tessa, Catrina, and Max.”

“Max?” a combination of adrenaline and whatever drugs the man had given me allowed me to sit up and begin throwing the blankets off.”

“Woah,” the man said, grabbing my shoulders. “You need to be careful, you’ve just had major surgery Alec.”

“Get Magnus,” I all but demanded as he settled me back into the bed.

“Promise you’ll stay put?” the man asked.

“Fine,” I said shortly. “I’ll stay.”

The man left with a small bittersweet smile on his face.

Magnus came bursting into the room a moment later. He didn’t say anything before curling into me on the bed.

I didn’t say anything either, just wrapped an arm around him. “You’re wearing my sweater,” I murmured after a few moments, pressing a kiss to Magnus’ forehead. “You wanna talk about it?”

“Not really,” Magnus murmured, burying his face in my chest. “You were unconscious for a month Alexander!”

“I’m sorry Magnus,” I said. “How’s Max?”

Magnus brightened a bit, “He’s small,” Magnus told me. “Comes with being early I guess.”

“But healthy other than that?” I made sure to ask.

“He’s perfect,” Magnus assured me. “Hold on, I’ll go get him.”

Magnus stood, pressing a kiss to my forehead as he left the room. He came back in a moment later, a small bundle held in his arms like it was the most precious thing he had ever held. “Here he is,” Magnus murmured, sliding back into bed next to me.

Magnus carefully passed Max over to me. My arms automatically adjusted and it felt just as natural as it had the first time I had held my brother Max. I smiled softly, running a finger over his cheek as he slept. “I remember the first time I held my brother Max,” I said quietly, “He was the smallest thing I’d ever seen, but he looked up at me, and he smiled, and I knew I would do anything to keep him safe. And look how that turned out.” I looked up at Magnus, already feeling the tears building in my eyes. “What if it happens again?”

“Max’s death wasn’t your fault,” Magnus said gently but firmly. “And our Max will be fine, he has so many people looking out for him.”

I opened my mouth to say something else, but I was interrupted by my own yawn. I leaned against Magnus’ chest, eyes starting to slip closed.

“Get some sleep,” Magnus said quietly, taking Max and helping me lie down. “I’ll be right back.”

I hummed in agreement, but I fell asleep before he had even left the room.

* * *

“Glad to see you’re finally up and about,” Catarina said when I entered the living room, settling in a chair, “Magnus was unbearable while you were unconscious.”

“Catrina, be nice,” Magnus chastised gently, crossing to the chair next to mine.

“Now where’s the fun in that?” she asked, sitting up on the couch with a stretch. “I have to go to work.”

“Thank you for your help, Catrina,” Magnus said, waving a hand to open the door as she left.

“How many people have been in and out of our apartment while I was out?” I murmured from my chair.

“Well there were your siblings and their partners,” Magnus started, counting on his fingers, “Jocelyn and Luke came by, Catarina came to check on you and Max, Raphael came and bummed on the couch for a while, and Tessa and Jem have been here since two days after the ritual.”

“I think I may have snapped at Jem when I woke up,” I murmured as Magnus managed to slide into the chair next to me. “I didn’t recognize him.”

“It’s fine,” Magnus murmured, running fingers through my hair, “He was a Silent Brother, I’m sure he’s dealt with worse than a moody Shadowhunter.”

I looked up at Magnus, he had his eyes closed, head tilted back against the back of the chair. There was an expression on his face that I couldn’t quite understand. “Hey,” Magnus opened his eyes and looked down at me. “You okay?”

It didn’t seem like he was going to answer for a moment, but he sighted and readjusted a bit. “You died,” Magnus said quietly. “Your heart stopped and you died three times before we delivered Max, and twice more after. I was terrified I was going to lose you. And it was all my fault. I messed up the exorcism and it nearly cost you and Max your lives.”

“Hey.” I turned to look Magnus in the eyes more easily. “It was not your fault. The demon said it was going to take everything from me, you saved me, Magnus.”

Magnus smiled, leaning forward a bit to press a gentle kiss to my lips. “I may need you to remind me of that every now and then,” he murmured, resting his forehead against mine.

“I can do that,” I agreed. “I love you.”

Magnus’ smile brightened and he pressed another, longer kiss to my lips. “I love you too Alexander.”


End file.
